The present disclosure is generally directed to toner compositions, and more specifically, to toner compositions including polymeric additives.
Electrophotographic printing utilizes toner particles which may be produced by a variety of processes. One such process includes an emulsion aggregation (“EA”) process that forms toner particles in which surfactants are used in forming a latex emulsion. See, for example, U.S. Pat. No. 6,120,967, the disclosure of which is hereby incorporated by reference in its entirety, as one example of such a process.
Combinations of amorphous and crystalline polyesters may be used in the EA process. This resin combination may provide toners with high gloss and relatively low-melting point characteristics (sometimes referred to as low-melt, ultra low melt, or ULM), which allows for more energy efficient and faster printing. The use of additives with EA toner particles may be important in realizing optimal toner performance, especially in the area of charging.
Issues which may arise with toners include their sensitivity to environmental conditions, including humidity. For example, in the summer months, when it is hot and humid, user complaints arise with respect to the background of an image. In the winter months, when it is cold and dry, light image complaints arise. There may also be a decrease in charge with developer aging, leading to excessive background.
There is a continual need for improving the additives used in the formation of EA ULM toners. There is also a need to improve the sensitivity of toner compositions to environmental conditions, including relative humidity.